Integrated circuitry fabrication in semiconductor processing typically forms contact openings, passageways or vias through insulating materials for interconnecting different conductive components. Further, integrated circuitry fabrication typically forms conductive metal lines as transistor gate lines or for interconnecting, energizing or accessing different electronic components.
A typical method of forming contact openings and metal lines is by subtractive etching using one or more masking layers. One exemplary masking material is photoresist. At the completion of the etching using a photoresist masking layer, the photoresist is typically etched from the substrate and does not constitute a part of the finished circuitry construction. In certain instances, the act of etching the photoresist from the substrate can leave undesired polymer residue over the conductive lines or within the contact openings. This has become particularly problematic as the dimensions of openings and lines are becoming ever smaller to enable maximizing circuit density.
One exemplary process and aqueous solution for removing polymer residue from a substrate in such instances is described in an article of Micro, June 2001, entitled “Removing postash polymer residue from BEOL structures using inorganic chemicals”. Such utilizes a solution composed of sulfuric acid, hydrogen peroxide, hydrogen fluoride and water.
One material presently finding use in the formation of conductive lines in semiconductor fabrication is elemental aluminum or aluminum alloys. Unfortunately, the sulfuric acid, hydrogen peroxide and hydrogen fluoride solutions presently being used can also significantly etch aluminum and aluminum alloys. Accordingly, care is taken when utilizing such solutions to ensure that the substrates are exposed to such solutions effective to remove the polymer residue, but not to a degree to significantly etch aluminum containing lines or other structures on the substrate. The present method by which this is achieved is in use of spray-rinse processors which, over a short time interval, spray the substrates with the solution. This is rapidly followed by a substantially pure, de-ionized water rinse.
While the invention was motivated in addressing the above issues and improving upon the above-described drawbacks, it is in no way so limited. The invention is only limited by the accompanying claims as literally worded (without interpretative or other limiting reference to the above background art description, remaining portions of the specification, or the drawings), and in accordance with the doctrine of equivalents.